Our Gemara on Amud Beis informs us that each Jewish Tribe had in its portion in Israel with at least some land in the mountains, and some in the lowland, and some in the countryside, and some in the valley.
Why is this important for us to know? There is this idea that each tribe has a particular role and perspective within Torah observance. We may deduce this logically, because otherwise, unless each tribe’s culture and approach has something unique to offer the republic, what is the point in the heterogeneity of Twelve Tribes? This is alluded to in the flags assigned to each Tribe as related in the Bible. (See Bamidbar chapter 2 and Midrash Rabbah ibid.)
Related to this, Noam Elimelech (Beshalach 5) states that it is impossible for a person to properly fulfill all the mitzvos in the Torah, with each of their details and strictures. However, if a person decides to focus on fulfilling one specific mitzvah with all its details and requirements, when Hashem sees this good faith effort, He provides supernatural assistance in fulfilling all the mitzvos properly. This is what is meant when Rav Yosef asked Rabbah’s son, “Regarding which mitzvah was your father extra careful?” (Gemara Shabbos (118b) That is to say, it is theologically valid to focus on one specific mitzvah over others. Noam Elimelech does not say how that particular mitzvah is chosen.
Gemara Beitzah (11a) tells us that we cannot assume that a dove will return to its coop if it does not have a line of sight, even if it is within 50 amos. Thus, even a close-by coop that is around a corner would not attract the Dove back to its nest. The Ishbitzer (Beis Yaakov Vayechi 26), cites this Gemara, and compares the dove to a Tzaddik, and says that a Tzaddik cannot break his “line of sight” with a mitzvah that is tied to his Neshama, and thus may martyr himself even if it isn’t from the three sins that all must give their life for. He says every Jew has one mitzvah that is somehow tied deep to his neshama.
Likutei Halachos (Choshen Mishpat, Laws of Neighbor Damages 5.2) interprets the legal formulation of privacy rules metaphorically. Mishna Bava Basra (3:7) rules that a person may not open a window opposite another window. He explains that each person has a window open to the truth but cannot easily see the whole truth. Therefore, one might judge another person‘s observance as incorrect or imbalanced, but it is forbidden to look from your “window of the truth“ into another person's window. Meaning to say, be careful how you judge and what you assume. In any case, this too seems to imply that different Jews legitimately have different foci regarding their service of God, and mission in life.
We can then understand our Gemara’s statement about each tribe in a similar light. Having every kind of terrain within their territory speaks to this issue. Even though every Jew, and especially every tribe, might have a particular focus and talent in service of God, there is enough of every kind of terrain within their territory, to allow them to at least understand, and benefit from all aspects of the Torah.